Helium: Properties


Atomic

  • Atomic Mass: 4.002602
  • Electronegativity:
    • Absolute: 12.3 eV
  • Electron Affinity: 0 kJ mol-1
  • Polarizability: 0.2 3
  • Effective Nuclear Charge:
    • Slater: 1.7
    • Clementi: 1.69
    • Froese Fischer: 1.62
  • Radius:
    • Atomic: 128 pm
    • Van der Waals: 122 pm
  • Atomic Ionization Energies:
    • 1s : 2373 kJ mol-1
  • Successive Ionization Energies:
    • He - He + : 2372.3 kJ mol-1
    • He+1 - He+2 : 5250.4 kJ mol-1